A day near Worthing?

I am delivering training in Worthing in the beginning of December. I arrive on the red eye at Gatwick the day prior. I would like to do something cool on that day in the area and looked into a tour of Castle Arundel, but it is closed. A fellow trainer may join me and we are looking for something interesting to do for a few hours and any restaurant recommendations. A friend of mine is from Worthing (grew up there) and he said there's absolutely nothing to do there which is why he moved. Please prove him wrong. Thanks.